Question

What is the y intercept of the quadratic function f(x)=(x-8)(x+3)

A) (8,0)

B) (0,3)

C) (0,-24)

D) (-5,0)

Answer 1

$f(x)=ax^2+bx+c\\\\\text{The y-intercept}\ (0;\ c)\\\\f(x)=(x-8)(x+3)=(x)(x)+(x)(3)-(8)(x)-(8)(3)\\\\=x^2+3x-8x-24=x^2-5x-24\\\\Answer:\ C)\ (0;\ -24)$